1. Field of the Invention
The present invention relates to a novel articulated element anchorage device or system having a cranked shape for use in any soil by way of known positioning processes such as, for example, pile driving, vibrodriving, propulsion, and driving with a monitor and suction as is the case with loose soils, as well as for providing fixed anchorage points in water and, in particular, at port installations such as, for example, marinas, mooring pontoons, etc.
2. Description of the Prior Art
In, for example, French Pat. No. 79/00.038 an anchorage system is proposed with a free rotation of the fastening point situated forwardly of the center of gravity with respect to the end driven into the ground, but the positioning of the system is effected by pulling on the cable.
U.S. Pat. No. 3,282,002 proposes an anchorage device with free rotation of the fastening point provided with a flat plate adapted for rocking, with the angular movement of this plate being limited by a stop. However, the flat plate does not pivot by itself, but requires the assistance of a spring, even an explosive, so that it locks the anchorage device.
U.S. Pat. No. 3,888,057 proposes a device in which a tractive force must be exerted on an eye of a free mobile piece disposed centrally the anchorage plate so that a pin, perpendicular to the anchorage plate, and disposed in a front part close to the end driven into the ground may rise up and then cause the anchorage plate to rock. Thus, particularly in hard soils, the torque on the mobile part may be too small for the device to open and the plate will skid rearwardly without rocking.
Additional anchorage devices or systems are proposed in, for example, British Application No. 2,089,862, and French Applications Nos. 2,470,823 and 1,453,190, as well as U.S. Pat. No. 1,982,963.
To solve the problems encountered in the prior art, the question to be resolved, is how to provide high resistance anchorage points system on land and at sea which may reliably withstand a horizontal tractive force sloped upwardly and even vertically, between a ton and a hundred tons or so while being able to be positioned accurately and being adapted to accommodate all types of soils such as, for example, clay, sand, rocky soils, etc.
Anchorage piles or more generally groups of anchorage piles generally solve such a problem, but they have the disadvantage of being torn out when the vertical force applied is too great.
Some special anchors based on the principle of pivoting due to the off centering of the pull of the cable on the plate offers very poor reliability for the probability of correct operation is too low.
The aim underlying the present invention essentially resides in providing a new anchorage device or system which resolves the problems encountered in the prior art.
The invention provides an anchorage device comprising an anchorage element adapted for penetrating into the ground under the action of driving, more especially percussion, forces, with the anchorage element comprising at least one main rigid body having at least one end for driving into the ground, and with the driving forces being exerted substantially in a driving plane passing through end for driving into the ground and a driving or propulsion axis related to the main body. At least one articulated element is pivotably connected to the main body and has a limited angular movement, with at least one anchorage line being connected to the main body by a flexible connection at at least one fastening point disposed between the driving end and the center of gravity of the bearing surface of the main body. The fastening point is disposed forwardly of a center of gravity, and the driving plane passes through the center of gravity.
According to the present invention, the at least one articulated element has a crank shape, and a center of gravity between the fastening point for the anchorage line and the articulation of the articulated element is located at a predetermined point. Moreover, the present invention contemplates an off centering with respect to the driving plane, on the one hand, of the fixed fastening point and, on the other hand, of the articulation, with the latter being situated along an axis perpendicular to the driving or propulsion axis in a part disposed opposite to the end driven into the ground or surface so that the application of a pull on the anchorage line causes the articulated element to rock and the anchorage element to pivot.
The forces, more especially percussion forces, impart to the anchorage element a so called driving-in energy.
The cranked shape of the articulated element may advantageously have a concavity turned to the side opposite said driving in end.
The combination described is capable of providing, during the pull T exerted by the anchorage line, the best locking position for the anchorage device.
It is adapted for causing it to move in the ground when it is subjected to these forces and for orientating it so as to present an optimum main cross section for mobilizing the maximum thrust of the ground. By main cross section is meant the contour of the section transverse to the axis of movement of the anchorage element.
By flexible connection is meant here a connection introducing substantially no moment of rotation at the fastening point to the plate, such as a connection by wire, chain, ball joint or by an articulated threaded rod.
Burying in the ground is effected by driving forces brought into play by techniques such as, for example, driving, vibrodriving, propulsion, driving in with monitor, even suction in the case of loose soil, all known to a man skilled in the art and the choice will depend on the nature of the soil.
The angular movement of the cranked articulated element may be in a range of between 30.degree. and 60.degree. and, preferably, close to 45.degree. with respect to the driving plane.